PROJECT SUMMARY Alzheimer's Disease and Related Dementias (ADRD) are among the most profoundly disabling and costly of all health conditions and the 5th leading cause of death. Family caregivers are at the forefront of managing ADRD across the continuum of care but are not routinely included in discussions about prognosis and are often poorly prepared to engage in surrogate decision-making. Compared to older adults without ADRD, those with ADRD are less likely to complete an advance directive and to formally designate a surrogate decision-maker, and are at heightened risk for unnecessary suffering and burdensome end-of-life care. Advance care planning seeks to improve communication about individual values, goals, and preference for care, but typically targets a specific decision, most often in the inpatient hospital or nursing home. Few interventions target advance care planning in primary care, which is where most persons with ADRD are initially diagnosed and medically managed. We propose a two-phase study of a multicomponent communication intervention, referred to as SHARING CHOICES, to proactively engage family and support advance care planning in primary care. Intervention components include: 1.) a letter from the primary care clinic introducing a new advance care planning initiative, 2.) person-family agenda-setting to align patient and family perspectives regarding the role of the family member in primary care interactions and stimulate interest in advance care planning, 3.) ongoing access to a non-clinician trained to lead advance care planning conversations, 4.) facilitated registration for the patient portal (for patient and family) to enable and extend electronic interactions and information access to family caregivers, and 5.) education and resources about ADRD for clinic staff. Study Aims reflect two phases that aligned with Stage I (refinement, pilot testing) and Stage IV (effectiveness) of the NIH behavioral intervention development Stage Model. First, we use a user-centered process to refine the protocol with input from primary care stakeholders (clinicians, case managers, staff, administrators), patients with ADRD, and their family caregivers. We will iteratively adapt and pre-test the protocol in 40 patient-family dyads at 2 primary care clinics. Aim 1 will yield a testable intervention protocol. Second, we test the effects of SHARING CHOICES on advance care planning outcomes among primary care patients with ADRD (mild-severe) and assess its implementation potential in a pragmatic cluster randomized trial at up to 100 diverse primary care clinics in 2 health systems. We hypothesize that intervention (versus control) patients will be more likely to have advance directive completion at 12 months and that among patients who die, those at intervention (versus control) clinics will be less likely to experience burdensome end-of-life care. We examine contextual factors that may facilitate or impede its dissemination and sustainability in primary care, using mixed methods. This study has the potential to change best practices in advance care planning in primary care.